...scientists in New Zealand and Canada examined the phenomenon Stephen Colbert, comedian and news satirist, calls "truthiness" -- the feeling that something is true.

When a decorative photograph appeared with the claim, people were more likely to agree that the claim was true, regardless of whether it was actually true.

Across all the experiments, the findings fit with the idea that photos might help people conjure up images and ideas about the claim more easily than if the claim appeared by itself. "We know that when it's easy for people to bring information to mind, it 'feels' right," said Newman. [emphasis mine]

I routinely add images to my AN posts. Making it easier for readers to conjure up images and ideas doesn't have to be manipulative. "Visually rich communication" is a communication skill that can be used for good or ill.